Catalyst



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Patented Nov. 21, 1933 ons n sr res ' isms (Granted under the act ofMarch 1883,, as

This invention described herein may be manuiactured and used by or forthe Government for Governmental purposes without the payment to me ofany royalty thereon.

This is a division of my application, Serial No. 304,162, filedSeptember 5, 1928, for catalysts and method of preparation.

My invention relates to catalysts, and more particularly to a method orpreparing metals and metallic compounds in the form of intimate,mixtures suitable for use as catalytic agents, and the productsproducedaccording to said method.

' it has been found that many chemical reactions are accelerated by thepresence of certain substances, mown in the science of chemistry ascatalyzers. In most cases the chemical reactions are still furtheraccelerated by the pres-" ence of certain additional substances. Theseadditional substances thatafiect the reaction are known as promoters.Thus, when a mixture of two or more substances is utilized as acatalytic agent to affect the speed of a reaction, one or more oi thesubstances may be the catalyst and one or more of the substances may bethe pro-' moter. Regardless oi the particular role each substance playsin accelerating the reaction, it has nevertheless been found that mostreactions are catalyzed more eficieniy by a mixture of substances thanby a single substance.

it is known that better catalytic efi'ects are obtained when the two ormore substances acting as the catalytic agent are intimately mixed.Heretofore, many attempts havebeen made to secure intimate mixtures ofthe substances effective as catalysts, but the attempts, while in someinstances producing somewhat satisfactory prod-' ucts, have been costly,resulting in a high cost of the catalyst.

At the present time it is the general practice to mix several metallicsalts, such as the nitrates "of several metals, and calcine the mixtureto form a mixture of the oxides. If it is desired to provide a metalliccatalyst, the oxides may be reduced. This method, although satisfactoryfor certain purposes, is not a complete success, as the resultingmixture is not as intimate as is possible to obtain, but is composed ofsmall particles or crystals of the several substances.

An object of my invention is to provide a catalytic agent that willaccelerate chemical reactions to a high degree.

- Another object of my invention is to provide' I catalytic materialcomposed of an intimate mixture of several substances.

Another object of my invention is to provide amended April so, was; etco. o. s

catalytic material formed or a plurality oi sub: stances in every activecondition.

.Still anotherobject of my invention is to devise a method oi preparingcatalytic material that will result in the production of a very intimatew mixture of the several substances.

With these and other objects in view which may be incident tomyimprovements, the invention consists in the product and method ofpreparing the same to be hereinafter set forth and claimed, @5 with theunderstanding that the several components entering into the compositionof the prod not, and the severalsteps of the method, maybe variedwithout departing from. the spirit and scope of theappended claims. 7

My invention consists in the provision of cata== lytic material and themethod of preparingv the same. According to my invention, the metals tobe used either in the'metallic state or in the form of metalliccompounds are fused together to iorm'an alloy. The alloy is formedbecause in the same the metals are most intimately mixed. The alloy isthen subjected to the action of chemicals. to form an intimate mixtureof metallic com pounds suitable for use as catalytic material. lin. someinstances it is desirable to reduce the metallic compoundsto an intimatemixture of the metals which will be in a form particularly desirable forcatalytically afiecting chemical reac= tion. According to my inventionit is desirable to secure the most intimate mixture of the com ponentsentering into the catalytic material that is possible. A solution of oneor more substances in still another substance constitutes a mixture ofthe components that is extremely intimate and approaches the intimacy ofcomponents of a chemical combination.

Alloys that are properly formed exhibit prop. erties similar to thoseof; solutions, and particu-- larly that of the intimacy of the mixtureof the components.

Since it is desirable to obtain a productiormed of intimately mixedcomponents, an alloy of the metals suitable for catalytic purposesserves as a convenient source from which the catalytic material can bederived. Consequently, my invention comprises the formation of an alloyof several metals and the subsequent treatment oi-the alloy to producethe catalyst desired. g ,In carrying out my invention it maybe desirableto-catalyze a reaction with a mixed catalyst containing iron and copperin a certain ratio.

In such a case, an alloy containing irpnand copper in the desired ratiowould be made up. As the 110.

catalyst so greatly afiects its value as an accelerator for chemicalreactions, it is absolutely essential that the components entering intothe alloy be completely fused and dispersed into each other so as toform a homogeneous mass.

The alloy may be cast into any desired shape, depending upon theparticular use to which it is to be subjected. desirable to have thecatalyst in the form of rods, bars, gratings, or as in my copendingapplication, Serial No. 113,830, filed June 4, 1926, in the form oftubes. In some instances it may be desirable to cast the alloy invarious other shapes which are most suitable for the purpose to whichthe catalyst is to be applied.

After the alloy is cast into a desired form and is set, it is subjectedto the action of an oxygenated atmosphere, at a temperature sufficientlyhigh to oxidize its surface. When the surface is oxidized to the desiredextent, the oxidation is stopped. The product of this treatment is amass of mate- 'rial of a desired shape having its surface covered with aporous mixture of the oxides of the several metals in the alloy.

For certain reactions where catalytic material formed of a plurality ofmixed oxides is desirable, the treatment just outlined is sufiicient.When used for such reactions, the catalytic material, after beingpoisoned, may be regenerated by subjecting the mass of material to anoxidizing treatment similar to that described in connection with thepreparation of the material. A case in which an oxidized alloy similarto that just described and containing copper and iron is desirable isthat in which carbon monoxide is-conv'ertedinto carbon dioxide such asdescribed in my copending application Serial No. 113,830, filed June 4,1926.

An oxidized alloy of iron and copper has been found to effect theconversion of carbon monoxide into carbon dioxide at relatively lowtemperatures.

The same mixture of oxides was found to catalytically accelerate'manyother reactions, such as the oxidation of sulphur to sulphur dioxide andthe oxidation of sulphur dioxide to sulphur trioxide which when absorbedin water produces sulphuric acid. Manganese may be added to either orboth of the metals referred to above to form catalysts having similareffects on the oxidation of carbon and sulphur oxides into higheroxides.

In many instances it is desirable to have as. a catalyst a mixture ofmetals in the form of a porous spongy mass. When such a catalyst isdesirable, an alloy of the desired composition is made up and cast inthe preferred shape. It is then oxidized into a condition such that allexposed surfaces are covered with a coating of the porous mixture of theoxides of the several metallic constituents.

After the oxidation is complete to the extent desired, the oxidized massis subjected to the action of-a reducing medium which removes the oxygenfrom the porous oxide coating and leaves the surface of the alloyed bodyin the form of a porous spongymass. This porous spongy mass of a mixtureof several metals is particularly desirable for use-as an acceleratingcatalyst in certain reactions.

Another method of preparing either a mixture of oxides or a spengymixture of metals is i to form a mixture of chemical compounds with saltforming substances.

In many instances it may be to form. mixed salts of the respectiveacidsor The salts or compounds formed can then be calcined into the mixedoxides of the metallic component of the alloys to be used as a mixedoxide catalyst, or if desired the oxides can be reduced to formtheporous spongy metallic coating on=the cast bodies similar to thatpreviously described.

In either of the methods so far described, the alloy is cast into a'formor body on which the catalytic material is formed. By so producing thecatalyst, the latter is securely held on the.

cast body as a base, in a manner such that it will be Well exposed tothe reaction it is to effect. After the catalyst is poisoned, either theoxide or the spongy metal mass may be reformed by subjecting the body toeither the oxidation or the oxidation and reduction treatment previouslydescribed. If necessary, the poisoned catalytic material can be scrapedor otherwise removed from the surface of the cast alloy and the lattersubjected to the necessary action to reform a catalytic surface of thedesired type.

A modification of the method of preparing catalysts according to myinvention is to first form an alloy of the desired metals and then grindthe alloy to either a fine powder or a granular form. For some reactionsthe powdered or granulated alloy will be sufficient. In other cases,however, it is necessary to oxidize the alloy. The oxidation can beeffected by treating the prepared alloy with oxygen as previouslydescribed. The oxidation may also be effected by first forming a mixedmetallic compound by treating the prepared alloy with-certain chemicals,and then calcining the mixed compounds to form the oxides.

When it is desired to prepare the powdered or granulated alloy in thespongy metallic form, the oxide is reduced by a treatment similar tothat described in connection with the catalysts formed on the alloyedbodies as a base.

In some pound can be reduced directly to the spongy metallic formwithout the necessity of first convert-.- ing to the mixture of oxides.

My invention may be applied to the utilization of any of the metalsdesired for catalytic purposes that will unite with other metals to formalloys. An alloy containing manganese, lead and copper wh'entreated wasfound to have properties desirable as catalyst. In this particularinstance, the tion:

Per cent Manganese 25 Lead 10 Copper Alloys of the following compositionwere also found to possess catalytic properties after treatment:

Y Per cent Manganese 25' Copper-" Per cent Iron 90 Copper 10 Alloyscontaining manganese and iron are eifective catalysts when treatedaccording to my invention. be obtained by treating alloys having thecomalloy was of the following composi-,

Desirable catalytic effects can also.

instances where compounds are formed with the metals of the alloy, thecomponents given in the three alloys tabulated above in varyingproportions.

In the application of my invention to the catalysis of chemicalreactions, it is necessary merely to form an alloy of the desired metalsand subject the alloy to any one of several treatments to obtain thematerial in the preferred form. Thus, if it is desired to producecatalytic material composed of a mixture of oxides, the alloy is castinto certain preferred shapes and the shapes are then subjected tochemical treatment, such as oxidation, by'subjecting the shapes to anoxygen treatment.

I'he cast alloy may be subjected to treatment with chemicals to form amixture of metallic compounds which may be calcined to the oxide.

When the spongy metallic form of catalyst is,

desired, the oxides are reduced by suitable reducing treatments.

If preferred, the alloy may be ground to varioussized particles and thensubjected to any of the treatments outlined above.

Thus it can be seen that my invention provides for the production ofcatalytic material formed of several substances, in a mixtureapproaching the intimacy ofthe constituents of a chemical compound.

My invention also provides for a support or base on which the catalyticmaterial is formed, and utilized. Thus, the alloy is cast into variousdesired forms which serve as thebasefor the formation of the catalyst.When catalysts are formed on a base according to my invention, and thecatalyst is poisoned, it may be scraped or otherwise removed from thebase material and the latter, which consisfs of the alloy, may beretreated. With such an arrangement, the cost of the catalyst can bereduced and its effectiveness increased, resulting in economical andemclent methods of catalyzing chemical reactions.

Although I have described the preferred embodiments of my invention, Iwish it to be understood that I do not confine myself to the precisedetails of compounding herein set forth, by way of illustration, as itis apparent that many changes and variations may be made therein, bythose skilled in the art, without departing from the spirit of theinvention, or exceeding the scope of 8 the appended claims.

I claim:

1. A catalyst comprising a base portion formed of an alloy containingcopper, iron and manganese, said base portion having intimately formedon the surfaces thereof, a mixture of metallic salts formed bysubjecting the alloy to an acid treatment.

2. A catalyst comprising a base portion formed of an alloy containingcopper, iron and manganese, said base portion having intimately formedon the surfaces thereof an intimate mixture of metallic compounds formedby subjecting the alloy to a chlorinating agent.

3. A catalyst comprising a base portion formed of an alloy containingcopper, iron and manganese, said base portion having intimately formedon the surfaces thereof an iniimatelmixture of metallic compounds formedby subjecting the alloy to a' nitrating agent.

4. A process of producing a catalyst comprising the steps of forming analloy of the desired catalytic metals, treating the alloys so formedwith a suitable chemical to form mixed salts or salt forming substanceson the. surface thereof, and calcining the substances so formed toobtain the mixed oxides of the metallic components of the alloysattached to the surface thereof.

5. A process of producing a catalyst comprising the steps of forming analloy of copper, iron 11%) and manganese, treating the alloys so formedwith an acid to form mixed salts or salt forming substances on thesurface thereof, and calcining the substances so formed to obtain themixed oxides of the metallic componentsof the alloy attached to thesurface thereof.

MAURICE E. BARKER.

